1. Field of the Invention
The present invention relates to a moving image converting apparatus, a moving image converting method, and a computer program. Particularly, in data conversion executed as data compression processing of moving image data, the invention relates to a moving image converting apparatus, a moving image converting method, and a computer program, which enable high-quality data conversion by suppressing image quality degradation, and also realizing compression that enables playback of high-quality images by performing compression processing in accordance with motion of the viewer's line of sight on played-back data.
2. Description of Related Art
Moving image data is converted, i.e., compressed to reduce its amount, for storage on a storage medium such as a hard disk or a DVD, or for distribution via a network. Particularly, with recent progress in quality enhancement for moving image data, such as high-definition data, the volume of data is drastically increasing. Under such circumstances, many discussions and studies are under way on technology regarding compression efficiency improvement in the processing of compressing/reconstructing moving image data, and quality degradation prevention for the reconstructed data.
Compression processing method for moving image data include, e.g., processing of decimating pixels forming image frames of moving image data, i.e., spatial decimation, and processing of decimation in terms of frame rate, i.e., temporal decimation.
Data reduction based on such data conversion provides an advantage that transmission of data for storage into a storage medium or via a network is performed efficiently. However, reconstruction of compressed data addresses a problem of image quality degradation. Particularly, when original data is a high-definition image, ins quality degradation becomes noticeable.
How such image quality degradation is reduced has been discussed variously. For example, Japanese Patent Application Publication No. 2005-198268 (Patent Reference 1) discloses an image compression processing configuration in which spatial, pixel decimation and temporal pixel decimation are switched according to the magnitude of the motion velocity of an object. Furthermore, Japanese Patent Application Publication No. 2006-5904 (Patent Reference 2) discloses a compress ion processing configuration in which sampling point phase changing processing according to the motion velocity of an object is added to the processing disclosed in Patent Reference 1, in spatial pixel decimation.